Prefixing is an option, however I see, and use, the SOLVED category as necessary to indicate the topic has come to some form or closure… whether actual solution or determination of no availed solution, or so off the tracks as now irrelevant to the OP (in which case topic closure is also recommended).
That was the case, however with the recent changes it is not so clear… I use Chrome, so for the most part it’s translation accuracy is sufficient (there are funny exceptions) that I can easily follow along and contribute - albeit in English if I don’t take time to manually translate back… which I usually don’t bother with.
One drawback to the segregation of language that I see, its that it is almost like a clique forming process… Those that understand participate, but others who normally would tend to contribute now stay out of it… I do see this as a potential fracture of the unity of a forum… Many hands, light work and all that being reduced to the few with both answers and language skills being the only ones to assist.